Running scripts

When any program is executed, the UnixWare 7 kernel looks at the first two characters of the file (the ``magic number'' header) to determine if it is a binary or a script. If the first two characters are #!, it is a script (shell, TCL, Perl, AWK or other script) that needs to be interperted by another program. The kernel then determines the absolute path of the script.

From UNIX mode:

• If the absolute path of the script begins with /linux, it changes root (see chroot(2)) to the /linux directory and executes the appropriate Linux interperter (determined from the first line of the script).

• Otherwise, it executes the appropriate UnixWare 7 interperter.

From Linux mode:

• If the absolute path of the script begins with /unixware it changes root to the /unixware directory and it executes the appropriate UnixWare 7 interperter.

• Otherwise, it executes the appropriate Linux interperter.

• If a Linux Bash shell script resides in /unixware, the system assumes it is a UnixWare 7 Bourne script, and it will not run properly. UnixWare 7 Bourne scripts residing under /linux encounter the opposite problem; they are assumed to be Bash scripts, and fail when the system attempts to run them as such. Scripts should be kept in the environments for which they are intended.

• The system detects scripts by the first two characters (#!). If you are working with a script that does not begin with #!, results are unpredictable.